const babel = require('@babel/core');
const sourceCode = `
<h1>
  hello<span style={{ color: 'red' }}>world</span>
</h1>
`;

const result = babel.transform(sourceCode, {
    plugins: [
        ["@babel/plugin-transform-react-jsx", { runtime: 'automatic' }]
    ]
});
console.log(result);

import { jsx as _jsx } from "react/jsx-runtime";
import { jsxs as _jsxs } from "react/jsx-runtime";
_jsxs("h1", {
    children: ["hello", _jsx("span", {
        style: {
            color: 'red'
        },
        children: "world"
    })]
});
